Brush seal
This invention relates to a method to improve the performance of standard brush seals for rotating shafts. This invention relates to a design that will lower manufacturing costs associated with standard brush seals for rotating shafts. This invention relates to a design that will improve wear characteristics of a standard brush seal. Specifically, the invention is intended to reduce manufacturing costs by combining the standard sealing element of a brush seal with the low cost materials and manufacturing methodologies of a carbon seal. Specifically, the invention is intended to lower the overall weight of the brush seal assembly, thereby improving the life of the brush sealing element and reducing the wear characteristics on both the seal element and the associated shaft.
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENTNot Applicable
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIXNot Applicable
BACKGROUND OF THE INVENTIONBrush seals are utilized in a wide variety of applications where high differential Pressures must be sealed against a rotating shaft. One of the most noteworthy applications is in the construction of both steam and gas turbines. Traditionally, highly precision carbon seals are used in these applications. Although carbon seals are inexpensive to manufacture, their sealing characteristics are poor in that they cannot come in direct contact with the associated shaft. The necessary gap assures that the abrasive carbon does not come in contact with the shaft being sealed, even during extreme thermal cycling. This necessary gap only marginally seals the application and allows a great deal of internal gas to pass through to the atmosphere or to other bearing components. Brush seals are commonly utilized to improve the sealing performance of these applications. However, brush seals have two distinct problems associated with the current state of the art.
First: Normally, a brush seal assembly is allowed to float in the seal housing of any given design so that it may normalize to the shaft being sealed. Because of the overall weight of current designs, brush seals require a heavy interference fit to the shaft. This heavy interference fit is principally done in an effort to extend the life of the seal by allowing greater eccentric wear as the seal drops during its life. This heavy interference fit does extend the life of the seal, however, it also decreases the life of the shaft. Because of the high loads associated with a fit of this nature, the shaft of the application is exposed to high abrasive loads that ultimately create unacceptable wear characteristics. Therefore, any brush seal design that can reduce the load of the interference fit will logically reduce shaft wear and extend the operational life of the equipment. This would have the effect of significantly lowering maintenance intervals, times to repair and remanufacturing costs.
Second: The design of currently available brush seals requires that they are imbedded into a heavy metal assembly, which must be manufactured against demanding tolerances. This, in turn, forces manufacturing costs up, which affects the selling price of the finished seal. In many cases a brush seal might be as much as 50 times costlier than its carbon counterpart. The high cost of current brush seal assemblies reduces their popularity and limits the number of applications that might otherwise use these seals. Therefore, any brush seal design that can significantly reduce manufacturing costs will provide a finished assembly that can be offered at a cost that will better compete with the more traditional carbon seals.
BRIEF SUMMARY OF INVENTIONThe invention is a unique arrangement of components that takes advantage of the low material costs and manufacturing costs associated with carbon, or other low cost, high performance materials, to improve the performance and lower the manufacturing costs of a brush seal. A brush seal element is embedded into a carbon, or other low cost, high performance material, carrier which carries a face groove and a counter bore. The face groove accepts the brush seal, which is held in place by pressing a carbon, or other low cost, high performance material, cap piece into the counter bore. Similarly, the carbon, or other low cost, high performance material, carrier can be designed to fix the seal element by bonding with glue, solder or integral molding.
Preferred Embodiment:
Claims
1. A brush seal configuration that may be manufactured at a reduced cost.
2. A brush seal configuration that will provide superior sealing characteristics.
3. A brush seal configuration that will provide extended life.
4. A brush seal configuration that will reduce wear on the mating components.
5. A brush seal configuration whose carrier is manufactured from carbon.
6. A brush seal configuration whose carrier is manufactured from a low cost, high performance material.
7. A brush seal configuration whose sealing element is bonded into its carrier.
8. A brush seal configuration whose sealing element is pressed into its carrier.
9. A brush seal configuration that utilizes a retention ring.
10. A brush seal configuration that utilizes a reinforcing ring.
Type: Application
Filed: Jul 18, 2011
Publication Date: Jan 24, 2013
Inventors: Jimmie Wade Hamilton (Pasadena, TX), Marc Wilburn Hickham (Friendswood, TX), James Wallace Greene (Pasadena, TX)
Application Number: 13/135,860